1. Field
Example embodiments of the present invention relate to methods of treating and removing a photoresist pattern and a method of manufacturing a semiconductor device using the same. Other example embodiments of the present invention relate to a method of treating a photoresist pattern and a method of removing a photoresist pattern formed using a photoresist composition suitable for argon fluoride (ArF).
2. Description of the Related Art
A photoresist pattern may be used in a photolithography process for patterning a substrate in a semiconductor device. The photoresist pattern is a material for forming a film whose solubility changes with an irradiation of light and/or a laser beam. The integrated degree of a semiconductor device may be improved as the resolution of the photoresist pattern and the light source are improved. Resolution of the light source may also be improved by shortening the wavelength of the light source. As the light source with a shortened wavelength is developed, the photoresist pattern suitable for the light source may also be developed. Examples of the photoresist pattern include I-line (365 nm) photoresist, KrF (248 nm) photoresist, ArF (193 nm) photoresist, and/or any other suitable photoresist.
A photolithography process using a KrF light source may have improved resolution and a depth of focus relative to an I-line light source. A photolithography process using a KrF light source may not, however, be effective in controlling a process due to the optical and chemical characteristics. When a chemically amplification type photoresist composition is used, a photoresist pattern may be formed by the catalysis of acid generated in a light-exposure process, unlike dissolution inhibition type photoresists used in a photolithography process using an I-line light source. When loss of acid is generated by base existing in the atmosphere or substrate, the pattern formed using the photoresist may be deteriorated.
A photolithography process using an ArF light source has been developed. For a photolithography process using the ArF light source, a photoresist composition suitable for ArF may be required. The photoresist composition for ArF may be a chemically amplified type photoresist like the photoresist for KrF. The photoresist for ArF may not include a polymer having an unsaturated bond (e.g., a benzene ring), unlike the photoresist for KrF. A polymer having a benzene ring may be used for the I-line photoresist and KrF photoresist, in order to guarantee resistance in a dry-etching process. If the benzene ring is used in the photoresist polymer for ArF, the benzene ring may absorb light having a wavelength of about 193 nm so that transparency of the photoresist is deteriorated and a lower portion of the photoresist may not be exposed to light. A photoresist having a polymer for ArF which includes a carbon-carbon single bond may be developed.
After the photoresist for ArF is used as an etching mask in an etching process, the photoresist for ArF may be removed by an ashing process using an oxygen plasma and/or an ozone gas. When the ashing process is performed using the ozone gas, damage to the substrate may be reduced relative to using the oxygen plasma. The photoresist pattern for ArF may be used for forming a semiconductor device having a line width of less than about 100 nm, but the photoresist pattern for ArF may not be removed well in the ashing process using the ozone gas.
In the ashing process using the ozone gas, the photoresist resin may be oxidized to be soluble in water, and then, removed. The photoresist for KrF may include an unsaturated bond (e.g., a benzene ring) so that the photoresist for KrF may be oxidized. The photoresist for ArF may include only a saturated bond (e.g., a carbon-carbon single bond) so that the photoresist for ArF may not be oxidized or removed using the ozone gas. In a conventional method of removing the photoresist, a carbon-carbon single bond in the photoresist resin may be cut off using the excimer light source to form a carbon-carbon double bond. The photoresist having the carbon-carbon double bond may be oxidized by the ozone gas. In the above method, an additional apparatus equipped with the excimer light source and extra processes may be required and problems (e.g., extension of the processing time and requiring an additional apparatus) may occur.